alien background creepy dark dead decay dez pain disease disgusting evil fill flesh ghastly graphic green halloween horrible internal organs liver meat meaty mummified offal organic organs red render rotten rotting scary shiny slimy texture ugly vector xymonau abstract biological blood body concept creation dissection gross growth gruesome infection jelly living matter membrane microscopic mucous nauseating ooze reflection science scientific sickening tumour veins wet yuck brain cancer cell division cells curdle petri dish yellow zombie apocalypse